Hi,
I've done some research on your request,
but I could not find very much to help you.
What I've found about
1) Connections
http://www.postgresql.org/idocs/index.php?runtime-config.html
enable LOG_CONNECTIONS (boolean), LOG_PID (boolean)
to log database users
2) Table locks
nothing
3) Consumed disk space of a specific database
All database related files are located in
$PGDATA/base/<database-name>
So, by summing all file sizes within this
directory, you should have it.
As far as I know, the only limitation to a
database is given by the total disk capacity.
I hope this helps at least a bit.
I've looked through the FAQ list too, but
couldn't find anything which might help you.
Still, I don't understand why nobody else is
answering.
Regards, Christoph